Const system names

[Pelle Månsson]

On 02/16/2010 04:27 PM, retard wrote:
> Tue, 16 Feb 2010 10:28:28 +0100, Lars T. Kyllingstad wrote:
>
>> bearophile wrote:
>>> Alternative names for the transitive const regime of D2, the main
>>> difference is that now immutable values are the default:
>>>
>>> - "immutable" ==>  (nothing, it's the default). - "const" ==>  "valview"
>>> (a local immutable value view of something). - mutable variable ==>
>>> "var"
>>> - "enum" ==>  "const" (or maybe it can be removed, so it becomes
>>> immutable, that is no annotation. The link-time optimization of LDC is
>>> able to remove unused values from the binary. Ten years from now all D
>>> compilers can be able to do this).
>>>
>>> [...]
>>
>> I don't agree that immutable should be the the default.  The default
>> should be the most common case, which is mutable.
>
> BTW, have you got some numbers from concrete examples such as real world
> programming projects. Note that many variables are not immutable in real
> projects, but they also could be:
>
> Integer boxedIntegerSum(Integer a, Integer b) {
>    Integer c = new Integer();
>    c.assign(a.getValue() + b.getValue());
>    return c;
> }
>
> Here you have three immutable variables a, b, and c. In reality they all
> could as well be constant references, a and b also could be immutable
> views:
>
> Integer boxedIntegerSum(immutable Integer a, immutable Integer b) {
>    const Integer c = new Integer();
>    c.assign(a.getValue() + b.getValue());
>    return c;
> }
Only if you're assuming that the assign() doesn't alter the integer, but 
in that case it's kind of meaningless. Also, requiring immutability for 
the input is not what you usually want.